Impact of elevated CO2 on feeding potential of wolf spider against brown planthopper (Nilaparvata lugens)

An experiment was conducted at Department of Entomology, Indian Agricultural Research Institute, New Delhi during 2015–16 and 2016–17 to study the impact of elevated CO2 on functional response of wolf spider, Pardosa pseudoannulata (Boesenberg and Strand, 1906) against brown planthopper, Nilaparvata lugens (Stal, 1854) (Hemiptera: Delphacidae). Spider feeding rate on BPH was higher in jar arena compared to microcosm arena both under ambient CO2 and elevated CO2 conditions. Regression of number of attacked prey (1/Ha) upon prey density per unit area (H) over time duration of experiment (T) in microcosm and in jar arena under ambient and elevated CO2 revealed type II functional response. Attack rate, maximum attack rate and efficiency parameters were higher and handling time was lower in both jar arena and microcosm under elevated CO2 condition compared to ambient CO2 condition. Simultaneously, predators might have consumed more number of preys due to their poor nutrient quality under elevated CO2 compared to ambient CO2. It was revealed that with increase of predator density within the same prey density in same area under both ambient and elevated CO2 conditions, the prey control might have optimized. This information generated would support the planthopper management by regulating predator number for increased predator efficiency.